Conductive foot covering



May 8, 1956 w, PRICE 2,745,041

CONDUCTIVEI FOOT COVERING Filed March 26, 1952 1N VEN TOR. 12

.1 1? 4/ RUSSELL MK pR/cs HTTOR VEV United States Patent CONDUCTIVE FOOT COVERING Russell W. Price, Newton, Mass. Application March 26, 1952,. Serial No. 278,556

Claims. (Cl. 317-4} This invention relates to a conductive foot covering, and more particularly to a conductive rubber designed to be worn over a shoe.

The invention has for an object to provide a novel conductive foot covering adapted to be worn over the shoe and capable of establishing a grounded connection between. the body of the wearer and a grounded floor or surface to the end that the risk. of explosion as a result of static spark from the wearer may be reduced to a minimum,

A further object of the invention. is to provide a novel. conductive foot covering, in the nature of a rubber designed to be worn over the shoe, thus enabling the body of the wearer to be grounded to a grounded floor or surface and thus prevent the development of a. static spark from the body of the wearer.

With these general objects in view, and. such others as may hereinafter appear, the invention consists in. the conductive foot covering hereinafter described andv particularly defined in. the claims at the end of this specification.

In the drawings illustrating the preferred embodiment of the invention, Fig. l is a perspective view of. the present conductive foot covering; Fig. 2 is a side elevation showing the conductive foot covering as worn over a shoe and with a conductive connector tucked into the shoe and under the heel of the wearer; Fig. 3 is a crosssectional view showing the conductive connector tucked into the shoe and extended laterally under the foot of the wearer; and Fig. 4 is a side elevation of a modified form of the invention wherein. a conductive connection may be wrapped about the wearers leg.

In general, the present invention contemplates an electrically conductive detachable foot covering adapted to be worn. by persons while working in. places where explosives or volatile liquids are present and which are particularly adapted to be used by surgeons and other hospital personnel in an; operating. room. where. explosive vapors and gases from volatile inflammable liquid anaesthetics, such as ether, may be ignited by sparks produced by the discharge of static. electric charges built up in. the body of the person. In accordance with thepresent invention, such static electric charges may be harmlessly discharged from the body of the person through the conductive foot covering and into the grounded floor of the hospital operating room. The illustrated conductive foot covering may and preferably will include a conductive rubber sole arranged to be easily slipped over the shoe, and provision is made for connecting a flexible conductor from the conductive sole directly to the body of the person to effect an eflicient discharge of any static electric charges as they are generated so that such charges cannot be built up to a point where an inadvertent discharge upon touching a metal or other object may cause a spark and ignite the explosive gases. An important advantage of the present invention flows from the fact that the operative, whether a surgeon, nurse or an industrial worker in an explosive plant, may wear the present foot covering over his own shoes with maximum comfort, and enabling the lCC hospital or plant to maintain or stock a few sizes which. can. be worn. by all. of the different personnel.

Referring now to the drawings, 10 represents the present conductive foot covering which for convenience ofv description may be termed or defined as a conductive slip-on and which is arranged to be readily attached to the shoe to form an efiicient ground connection from the body of the person to a grounded conductive floor upon which the person stands. As illustrated in Figs. l and 2,- the conductive slip-on includes a conductive sole portion 12 which may and preferably will comprise a conductive rubber sole having a high percentage of carbon to form an efiicient electrical conductor. The conductive rubber sole portion 12 may be molded integrally with a toe or upper portion. 14 of. the slip-on and provided with. an integral endless strap portion 16, the latter portions 14, 16 comprising the usual non-conductive and stretchable rubber to permit the slip-on to be worn on different sizes of shoes. When worn, the endless strap portion 16 may be stretched around the back of the shoe, as illustrated.

In order to provide an eflicient electrical connection between the conductive sole 12 and the body of the wearer, the conductive sole portion may be extended upwardly against one side of the upper portion. 14 at a point adjacent the rear of the sole to form :1 lug or terminal 18, and in the embodiment of the invention illustrated in Figs. 1 and 2, the terminal 18 is connected by a flexible conductive rubber strip 20 arranged to be guided along the side of the strap portion 16 through a suitable loop 22 to a terminal 24 at the back of the strap portion 16. The conductive rubber strip 20 may be secured to the terminals 18, 24 in any convenient manner such as by riveting, or as hereinshown, may be detachably secured by metallic snap fasteners 26, 28, and a second flexible conductive rubber strip 30 may be secured. to the back of the strap portion 16 between the strap portion and the end of the conductive strip 20 by the fixed element of the metal snap fastener. The detachable element of the snap fastener is connected to the strip 20 so that when assembled the snap fastener 28 forms an electrical con nection between the adjacent ends of. the conductive rubber strips 20, 30. The second conductive rubber strip 30 may be elongated and in use may be tucked into the back of the shoe and under the heel. of the wearer. In practice, the moisture of the foot caused: by normal perspiration forms an efficient conductive path from the persons body through the sock or stocking to the conductive rubber strip 30. Thus, any static electric charges built up in the persons body by friction while moving around or otherwise may leak harmlessly from the wearers body through the conductive strips 20,. 30 and the sole portion 12 into the grounded conductive fioor upon which the wearer stands.

In a modified form of the invention shown in Fig. 3, the second strip 30 may be eliminated, and the strip 20 may be tucked directly into the side of the shoe and extended laterally under the persons foot, as illustrated.

.Referring now to Fig. 4, the modification of the invention therein shown may comprise a conductive foot covering. or slip-on similar to that above described except that the flexible connection for conducting the static elec trio charges from the wearers body may comprise a con.- ductive metal ball and link chain 32, as illustrated, which may be connected at one end to the terminal 18 by a snap fastener 34, the other end of the chain being guided by weaving the same through openings 36 formed in one side of the strap portion 16 to extend the chain to the rear thereof, and the chain may then be extended upwardly and wound about the wearers leg, the end of the chain being connected to a portion of its length to form a loop about the leg, as illustrated. As herein shown, the looped end of the chain may be provided with a hollow split adapter 38 arranged to engage a ball on the chain, and in order to provide a fight engagement with the wearers leg the end of the chain may be provided with an elastic web 40 connected between the adapter 38 and a second adapter 42 connected to the chain. In practice, the wearer may roll down his sock oristocking and loop the chain about his bare leg to provide an eflicient body connection.

From the above description, it will be seen that the present conductive foot covering or slip-on may be used by workers in places where explosives are present and particularly by hospital personnel in operating rooms where explosive anaesthetics are used, the present conductive slip-ons permitting a continuous discharge of static electricity from the wearers body through the conductive foot covering and into a conductive and grounded floor upon which he is standing, thus preventing any substantial potential from being built up in the persons body which might otherwise create a spark and cause an explosion. It will also be seen that the present conductive slip-011s may be easily and conveniently slipped on or off when entering or leaving an explosive area, and that the present novel provision for direct engagement with the persons body assures a good conductive path for any static electricity from the body to the ground.

The present conductive slip-on possesses many commercial advantages over the custom-made conductive shoes which have heretofore been worn to some extent in the operating rooms of hospitals. In the first place,- the present slip-on lends itself to economical manufacture and may be sold at a fraction of the cost of the custommade and specially fitted conductive shoe. In addition, when worn over the shoe, the surgeon, nurse or industrial Worker is able to enjoy the comfort of his own shoe with the result that the normal resistance to purchasing and wearing expensive conductive shoes is overcome, thereby contributing to the more extensive use of the slip-on and to the safety in the operating room or explosive plant. In addition, the price at which these slip-ons may be sold enables the hospital or the plant to maintain a stock of a few sizes suflicient to permit the slip-ons to be worn by all the personnel because of the stretchable nature of the material of which the slip-ons are preferably constructed. Design of the slip-on does not interfere with any of the normal operations of the personnel and provides a convenient way of insuring against the development of inadvertent static sparks in dangerous explosive areas.

While the preferred embodiment of the invention has been herein illustrated and described it will be understood that the invention may be embodied in other forms within the scope of the following claims.

i Having thus described the invention, what is claimed is: 5 1. A conductive foot covering adapted to be worn over a shoe for minimizing the risk of explosion from static spark, said foot covering comprising a conductive halfsole portion, means for detachably connecting the conductive half-sole portion to the shoe, said means comprising a stretchable toe portion capable of accommodating the toes of a number of different sizes of shoes, and an endless stretchable strap formed integrally with the toe portion and adapted to extend around the rear of the heel portion of the wearers shoe and of stretching to enable the foot covering to be worn on shoes of different lengths, and a conductive heel strip of a width and length capable of being folded over the top of the heel portion of a low shoe and of being tucked down inside the shoe and under the heel of the wearer to assist in anchoring the heel portion of the foot covering upon the wearers shoe, and conductive means extending along said endless strap connecting said flexible conductive heel strip to the conductive sole portion of the shoe.

2. A conductive foot covering adapted to be worn over a shoe for minimizing the risk of explosion from static spark, said foot covering comprising a conductive halfsole portion, means for detachably connecting the conductive half-sole portion to the shoe, said means comprising a stretchable toe portion capable of accommodating the toes of a number of different sizes of shoes, and an endless stretchable strap formed integrally with the toe portion and adapted to extend around the rear of the heel portion of the wearers shoe and of stretching to enable the foot covering to be worn on shoes of difierent lengths, flexible conductive means adapted to engage the wearer and including a portion extending along said strap from the conductive sole portion of the shoe to approximately the point on said strap which engages the rear of the heel of the wearers shoe, and means maintaining said portion of said flexible conductive means in position relative to said strap.

3. A conductive foot covering as defined in claim 2, in which the portion of the flexible conductive means which extends along the strap includes a metal conductor laced through the strap, and wherein the flexible conductive means further includes a portion adapted to encircle the ankle of the wearer.

4. A conductive foot covering as defined in claim 2, in which the portion of the flexible conductive means which extends along the strap includes a strip of flexible conductive material overlying the strap and extending through at least one loop mounted on said strap.

5. A conductive foot covering adapted to be worn over a shoe for minimizing the risk of explosion from static spark, said foot covering comprising a conductive halfsole portion, means for detachably connecting the conductive half-sole portion to the shoe, said means comprising a stretchable toe portion capable of accommodating the toes of a number of different sizes of shoes, and an endless stretchable strap formed integrally with the toe portion and adapted to extend around the rear of the heel portion of the wearers shoe and of stretching to enable the foot covering to be worn on shoes of different lengths, a conductive heel strip carried by the rear portion. of said endless stretchable strap and of a width and length capable of being folded over the top edge of a low shoe and thence downwardly and forwardly to dispose the end portion thereof under the heel of the wearer to enable establishment of a firm conductive connection to the foot as the wearer stands, and means for conductively connecting the heel strip with the conductive halfsole of the shoe covering.

References Cited in the file of this patent UNITED STATES PATENTS 1,940,491 Freitag Dec. 19, 1933 2,079,331 Nyhagen May 4, 1937 2,261,072 Monahan Oct. 28, 1941 2,287,744 Monahan June 23, 1942 2,526,774 Riley Oct. 24, 1950 2,586,747 Van Atta Feb. 19, 1952 2,701,323 Lewis Feb. 1. 1955 

